Skin-Contacting Tubular Fabric Underlay For Use Beneath A Therapeutic or Prosthetic Device

ABSTRACT

A skin-contacting fabric underlay for use beneath a therapeutic or prosthetic device on a human or animal body part is formed as a tube of knitted fabric. The yarns forming the fabric have a core of elastic material surrounded by moisture-transporting filaments of substantially non-elastic material, the yarn having elasticity, the fabric having a warp-knitted structure characterized by an artificial terry surface on an inner skin-contacting surface of the tube. The artificial terry surface is formed by underlaps of the yarn, in which the elasticity of the yarn causes the underlaps to draw up and form artificial terry loops that contact the skin of the body part about which the tube is sleeved. The artificial terry loops serve to space overlaps of the yarn from the skin and to move moisture away from the skin.

BACKGROUND OF THE INVENTION

The present disclosure relates generally to fabric underlays for use as a skin-contacting layer beneath a therapeutic device (e.g., a cast, a splint or immobilizer, a medical dressing, etc.) or prosthetic device (e.g., a prosthetic limb). The disclosure additionally relates to tubular fabrics for constructing underlays.

When any device, such as a therapeutic or prosthetic device, is secured about a human or animal body part for an extended period of time (e.g., weeks or months), health of the skin beneath the device becomes an issue of concern. Moisture from perspiration or other source, trapped beneath the device for an extended time, can create problems such as bacterial or fungal growth. Additionally, contact dermatitis can be caused by the constant contact of a foreign material with the skin.

It is common to wrap the body part with a fabric before placing additional materials (e.g., padding for a cast, the cast material, or a prosthesis) about the body part. For example, in the case of casting, weft-knit fabric is commonly employed as an underlay. The weft-knit fabric is commonly made of 100% cotton or a cotton/polyester blend, and is formed on a circular knitting machine as a continuous tube of fabric, wherein the yarn forming a given course of knit stitches runs generally circumferentially of the tube. Such weft-knit material, because of its conventional weft-knit structure and the types of material commonly employed, is not particularly effective at keeping moisture away from the skin.

It is desired to improve upon such conventional fabric underlay materials.

BRIEF SUMMARY OF THE DISCLOSURE

The present disclosure describes a fabric underlay that is thought to improve upon conventional fabric underlay materials, particularly with respect to moisture transport properties. In one aspect of the invention as described herein, a skin-contacting fabric underlay for use beneath a therapeutic or prosthetic device on a human or animal body part comprises a seamless tube of fabric knitted from yarn. The yarn, which has elasticity, has a core of elastic material surrounded by moisture-transporting filaments of substantially non-elastic material. The filaments are arranged so as to allow the yarn core to stretch resiliently. The fabric has a knitted structure characterized by an artificial terry surface on an inner skin-contacting surface of the tube, the artificial terry surface being formed by underlaps of the yarn, the elasticity of the yarn causing the underlaps to draw up and form artificial terry loops that contact the skin of the body part about which the tube is sleeved. The artificial terry loops serve to space overlaps of the yarn from the skin and to move moisture away from the skin.

In some embodiments of the invention, the fabric is formed on a circular warp knitting machine having a single ring of needles and having an outer guide ring and an inner guide ring each threaded with yarn.

The term “artificial terry” as used herein refers to a knit structure that is not a true terry knit but that exhibits terry-like loops in contact with the skin. In the described embodiments, as noted, the artificial terry loops are formed by underlaps of the yarns. Preferred knitted structures for purposes of the present invention have underlaps across two needles (as opposed to only one needle), although single-needle underlaps can be employed and are included in the scope of the invention.

In some embodiments of the invention, the filaments are air-jet-entangled about the core of the yarn, and the filaments are made of a synthetic polymer material. Such yarns are often referred to as “air-covered” yarns. In some such air-covered yarns, usable in the practice of the present invention, the filaments define one or more grooves in an outer surface of each filament extending longitudinally of the filament for inducing a capillary effect to transport moisture longitudinally of the filament. The filaments can be made of a polyester. The ability of such yarn to transport moisture longitudinally along the yarn, synergistically working with the knit structure of the fabric, in which the yarns extend generally longitudinally along the tube rather than circumferentially as in conventional circular weft-knit fabrics, provides the fabric underlay with a marked ability to transport moisture longitudinally along the fabric tube.

Additionally, the artificial terry loops lift the bulk of the fabric off the skin and thus reduce overall surface area contact with the skin. These characteristics work together to substantially increase the ability of the fabric underlay to keep moisture away from the skin, relative to the above-noted conventional weft-knit underlay materials.

In preferred embodiments, the core of the yarn is made of spandex. The spandex can comprise up to about 20 wt % of the fabric. Relatively low percentage of spandex (e.g., less than about 5 wt %, more preferably less than about 2 wt %) is generally preferred for most applications.

Various knitted structures can be used in the practice of the invention. As one example, the structure can be a tricot knit. In one such embodiment, the tricot knit is characterized by a 1-2/1-0 lapping of the yarns fed by the outer guide and a 1-0/1-2 lapping of the yarns fed by the inner guide.

As another example, the knitted structure can be a locknit. In one such embodiment, the locknit is characterized by a 1-2/1-0 lapping of the yarns fed by the outer guide and a 1-0/2-3 lapping of the yarns fed by the inner guide.

Various yarns of the filament-wrapped core type can be employed, in various sizes. Generally, the elastic core of the yarn can have a size from about 10 denier to about 500 denier. In one embodiment, the core is spandex and is approximately 10 to 20 denier in size.

The yarn can have a size from about 40 denier to about 840 denier. In one embodiment, the yarn has a denier of about 150 to 200.

The knitted fabric tube in a relaxed state can have a diameter ranging from about 0.5 inch to about 20 inches, for a variety of uses on a variety of body parts (e.g., fingers, hands, wrists, elbows, upper arms, thighs, knees, calves, shins, feet, torsos).

Fabric underlays in accordance with the present disclosure can have various configurations depending on the particular application. In some embodiments, the fabric underlay is configured to be sleeved over the lower arm, wrist, and hand of the wearer. The underlay can be fashioned to encase and isolate a finger from other fingers, or to isolate each of a plurality of fingers and/or the thumb, or to isolate a group of adjacent fingers from other fingers.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1 is a photograph of a generally tubular fabric underlay in accordance with one embodiment described herein;

FIG. 1A is a photograph of a distal portion of the underlay of FIG. 1;

FIG. 2 is a photograph of a generally tubular fabric underlay in accordance with another embodiment described herein;

FIG. 2A is a photograph of a distal portion of the underlay of FIG. 2;

FIG. 3 is a photograph of an underlay in accordance with a further embodiment sleeved over the lower arm and hand of a wearer;

FIG. 3A is a photograph of the hand region of the underlay of FIG. 3;

FIG. 3B is another photograph of the hand region of the underlay of FIG. 3;

FIG. 4 is a photograph of the hand region of an underlay in accordance with yet another embodiment;

FIG. 5 is a photograph of a tubular fabric underlay in a partially fashioned condition;

FIG. 5A is a photograph of the underlay of FIG. 5 in a laterally stretched condition to show the rib structure of the knit on the outer face of the fabric;

FIG. 5B is a photograph of the underlay of FIG. 5 in an inside-out and laterally stretched condition;

FIG. 5C is a photograph of the underlay of FIG. 5 in an inside-out and laterally stretched condition, and on an enlarged scale to show details of the knit construction;

FIG. 6 is a photograph of an underlay in accordance with a still further embodiment;

FIG. 7 illustrates a knitted structure for a skin-contacting fabric underlay in accordance with one embodiment;

FIG. 7A shows the lapping diagrams for yarns fed by the outer guide ring and by the inner guide ring to make the knit structure of FIG. 7;

FIG. 8 illustrates a knitted structure for a skin-contacting fabric underlay in accordance with another embodiment;

FIG. 8A shows the lapping diagrams for yarns fed by the outer guide ring and by the inner guide ring to make the knit structure of FIG. 8;

FIG. 9 is a magnified depiction of one type of air-covered yarn that is useful in the practice of the present inventions;

FIG. 10 is a diagrammatic depiction of a cross-section of a filament of the air-covered yarn in accordance with one embodiment of the inventions.

DETAILED DESCRIPTION OF THE DRAWINGS

The present inventions now will be described more fully hereinafter with reference to the accompanying drawings in which some but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

As noted, the present inventions in at least some embodiments aim to improve upon conventional circular weft-knitted fabric underlays such as the commonly available weft-knit types. Knitted fabric underlays in accordance with the invention can improve upon such weft-knit and similar materials particularly as regards the ability of the underlay to transport moisture away from the skin and longitudinally along the tubular underlay.

The skin-contacting knitted fabric underlays of the inventions can be formed on various warp-knitting machines of various designs and principles of operation. Non-limiting examples include: circular warp-knitting machines; Raschel machines having double needle bars, plus a spike bar for artificial terry loop formation; flat-bed tricot machines; and the like.

With respect to circular warp knitting machines, the fabric can be made on such a machine having a single circular row of needles to which two sets of yarns are respectively fed by an outer guide ring and an inner guide ring, which are analogous to the back guide bar and front guide bar of a flat warp-knitting machine. The needles are vertically reciprocated in tricks defined in a stationary cylinder, and a rotating cam arrangement imparts the vertical movement to the needles. The machine includes mechanisms for imparting clockwise and counterclockwise motions to each of the guide rings, which motions are analogous to the shogging motions of the guide bars in a flat warp-knitting machine, and which are hereafter referred to as “shogging” of the guide rings. The machine includes further mechanisms for imparting radially inward and radially outward movements to the yarns being fed to the needles, which movements are analogous to the swing movements of the guide bars in a flat warp-knitting machine, and which are hereafter referred to, for convenience of description, as “swinging” of the guide rings, even though it will be understood that the guide rings themselves of course do not undergo a swinging movement since they are constrained to undergo only a rotational or shogging motion. There are various approaches to accomplishing the required shogging and swinging movements in a circular warp-knitting machine, which are known to those skilled in the art, and the present invention is not limited to any particular approach. Specific machine mechanisms for making the fabrics described below will not be described, since, as noted, various approaches known in the art are possible and would be apparent to one skilled in the art having the benefit of the following description.

FIG. 7 is a diagrammatic depiction of a knit structure for a tubular skin-contacting fabric underlay for use beneath a therapeutic or prosthetic device on a human or animal body part, in accordance with one embodiment of the invention. FIG. 7A shows the lapping patterns for the yarns fed by the outer and inner guide rings for making the knit structure of FIG. 7. The knit structure of FIG. 7 is a tricot structure or pattern, in which there are single-needle underlaps of the yarns fed by the inner guide ring. These underlaps contact the skin when the tubular fabric underlay is sleeved over a body part. The yarns fed by the guide rings preferably (but not necessarily) are all identical and have a core of elastic material surrounded by moisture-transporting filaments of substantially non-elastic material. FIG. 9 depicts an example of a yarn of this type, specifically showing an air-covered yarn in which the filaments 10 are air-jet-entangled about the core 12. The filaments are arranged so that the core is able to resiliently stretch, such that the yarn has elasticity. An artificial terry surface is created on the inner skin-contacting surface of the tube, the artificial terry surface being formed by the underlaps of the yarn. More particularly, the elasticity of the yarn causes the underlaps to draw up and form artificial terry loops that contact the skin of the body part about which the tube is sleeved, the artificial terry loops serving to space overlaps of the yarn from the skin and to move moisture away from the skin.

See also FIGS. 5A, 5B, and 5C, showing an actual fabric constructed in accordance with the present disclosure.

FIG. 10 shows in schematic fashion a section of one filament 10 in accordance with a one possible embodiment, in which each of the filaments has a cross-section characterized by one or more grooves 14 extending longitudinally along the filament. The depicted cross-sectional shape is merely exemplary, and there are many variations on filament cross-sectional shapes providing one or more longitudinal grooves that can be used in the practice of the present invention. The important aspect is that a capillary effect is provided by each groove 14 for moving moisture longitudinally along the groove, whereby the yarn as a whole has the ability to move moisture longitudinally along the yarn because except for the loops, buckles, and horseshoes present in an air-covered yarn such as shown in FIG. 9, the filaments extend generally longitudinally along the core (as opposed to, for example, a covered yarn in which the wrapping filament extends generally circumferentially).

The filaments 10 can be formed of polyester, although other materials may be useful in some cases. The core 12 can be formed of spandex, also known as elastane. Generally, the elastic core 12 can have a size from about 10 denier to about 500 denier. In one embodiment, the core is spandex and is approximately 10 to 20 denier in size.

The yarn as a whole can have a size from about 40 denier to about 840 denier. In one embodiment, the yarn has a denier of about 150 to 200.

In one preferred embodiment of the invention, the fabric underlay is constructed of substantially 100% air-covered yarn of the type describe above.

FIG. 8 is a diagrammatic depiction of a knit structure for a tubular skin-contacting fabric underlay for use beneath a therapeutic or prosthetic device on a human or animal body part, in accordance with another embodiment of the invention. FIG. 8A shows the lapping patterns for the yarns fed by the outer and inner guide rings for making the knit structure of FIG. 8. The knit structure of FIG. 8 is a locknit, in which there are two-needle underlaps of the yarns fed by the inner guide ring. The lapping pattern for the outer guide ring is 1-2/1-0 (and repeat), and the lapping pattern for the inner guide ring is 1-0/2-3 (and repeat). Because the two-needle underlaps have greater lengths than the single-needle underlaps of the tricot fabric of FIG. 7, it is thought that the locknit underlaps may provide larger artificial terry loops and hence a more-effective artificial terry surface for the fabric underlay, relative to that of the tricot fabric.

Tubular fabric underlays in accordance with the invention can be formed in various diameters. For example, the relaxed diameter of the tube can be from about 0.5 inch to about 20 inches, depending on the particular body part the tube is to be used on.

Example 1

A tubular fabric underlay having a locknit structure of the type shown in FIG. 8 was made on a circular warp-knitting machine having a diameter of about 1 inch and having 36 needles. Each guide ring fed 36 air-covered yarns marketed under the trademark COOL-WICK® by Sapona Manufacturing Company, Inc. of Cedar Falls, N.C. All yarns were identical, having a spandex core of about 20 denier and approximately 96 polyester filaments air-jet-entangled about the core, the yarn having an overall denier of about 170.

Example 2

A second tubular fabric underlay having a locknit structure of the type shown in FIG. 8 was made on a circular warp-knitting machine having a diameter of about 2 inches and having 60 needles. Each guide ring fed 60 of the above-described air-covered yarns.

Example 3

A third tubular fabric underlay having a locknit structure of the type shown in FIG. 8 was made on a circular warp-knitting machine having a diameter of about 3 inches and having 96 needles. Each guide ring fed 96 of the above-described air-covered yarns.

Example 4

A fourth tubular fabric underlay having a locknit structure of the type shown in FIG. 8 was made on a circular warp-knitting machine having a diameter of about 4 inches and having 120 needles. Each guide ring fed 120 of the above-described air-covered yarns.

Fabric underlays formed in accordance with the invention have several beneficial properties. They are form-fitting about the body part, because of the resiliency resulting from the knit structure and the elasticity of the yarns making up the fabric. As noted, the tubular fabric underlay has the ability to move moisture away from the skin and longitudinally along the tubular underlay, because of the knit structure in which the yarns extend generally longitudinally along the tube and because of the ability of the yarns to move moisture longitudinally along the yarns. This is advantageous in an application such as a cast underlay, because the underlay is able to move moisture longitudinally from a middle region of the cast to an open end of the cast where evaporation of the moisture can take place more rapidly because of greater exposure to air.

Exemplary tubular fabric underlays of various configurations will now be described with reference to FIGS. 1 through 6. An underlay in accordance with aspects of the present inventions is formed by first forming a tube of the above-described fabric or any other suitable fabric construction. In the case of a circular-knit tube, the tube will be seamless. In the case of a flat-bed-knit fabric, a tube can be formed by seaming or serging the two longitudinal edges of the fabric together. The tube can be longer than what is needed for the application. Thus, in some cases, a roll of tubular fabric can be provided to the medical practitioner, such as in a corrugated paperboard box-type dispenser having an opening through which a desired length of the tube can be withdrawn and cut off for subsequent use by the practitioner. In other cases, the practitioner can be provided with pre-fabricated tubes of a range of different lengths and/or a range of different diameters, and the practitioner can select the appropriate length and/or diameter for the particular application. In the case of pre-fabricated tubes, the tubes can be serged at one or both ends, if desired.

The tube of fabric can then be modified by operations such as cutting or slitting part of the tube length, sewing or stitching, etc., so as to conform the fabric to the body part being treated. For example, when preparing a patient's hand and lower arm for casting to treat a fracture or other condition requiring immobilization, the tube can be slit at its distal end (i.e., the end corresponding to the hand, as opposed to the proximal end that is closer to the elbow) for a predetermined length and the resulting fabric edges (see FIG. 5) can be sewn or stitched or serged to form two tubes of smaller diameter each of which can receive a finger or two adjacent fingers. FIGS. 1 and 1A, and FIGS. 2 and 2A, for instance, show the fabric tube having been slit. Two of the fabric edges are then joined together by any suitable technique as noted, and the other two edges are similarly joined together. The joining technique for making one of the finger-receiving tubes can be, but need not be, the same as that used for making the other finger-receiving tube. More than two such finger-receiving tubes can be made, if desired. The various finger-receiving tubes can be, but need not be, equal in diameter. For example, a larger tube can be formed for receiving two adjacent fingers, and another tube can be made for receiving a single finger. See, for example, FIGS. 3, 3A, and 3B.

FIGS. 2 and 2A additionally illustrate that a thumb hole 20 can be formed for receiving the patient's thumb therethrough. The thumb hole can easily be formed by the practitioner in the needed location for the particular patient. For example, using a scissors to slightly nick the fabric at the desired location for the thumb hole is adequate for making the hole. An advantage of the above-described knitted fabric is that it is resistant to running or raveling. Thus, nicking the fabric to make the thumb hole does not result in the fabric running from that location.

As illustrated by FIGS. 3, 3A, and 3B, the finger-receiving fabric tubes can be made longer than the fingers and can be folded back over the finger(s) to form a double layer of fabric, if desired. Additionally, a thumb-covering fabric can be added by using a smaller-diameter tube of fabric and sleeving it over the thumb.

FIG. 4 illustrates yet another variation of underlay, in which the index and middle fingers are kept together (i.e., cannot be spread apart) but are isolated from skin-to-skin contact with each other. This is accomplished by providing a “divided” finger-receiving tube made by fashioning a tube of a size suitable for receiving both fingers, and then stitching or otherwise dividing the tube into two adjoined tubes each for receiving one finger.

FIG. 6 illustrates that two finger-receiving tubes can be formed generally as previously described, and one tube can be serged for a distance from its distal end partway toward its opposite end that joins with the other finger-receiving tube. The remaining length of the serged tube can be stitched so that the seam presents as little bulk as possible. The other tube can likewise be serged and stitched, or can be stitched for its entire length, again for presenting as little bulk as possible between the adjacent fingers.

Those skilled in the art, based on the present disclosure, can easily envision other variations of underlays for treating various body parts.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. 

What is claimed is:
 1. A skin-contacting fabric underlay for use beneath a therapeutic or prosthetic device on a human or animal body part, comprising: a tube of knitted fabric formed on a knitting machine from two sets of yarns, the yarns having a core of elastic material surrounded by moisture-transporting filaments of substantially non-elastic material, the yarns having elasticity, the fabric having a knitted structure characterized by an artificial terry surface on an inner skin-contacting surface of the tube, the artificial terry surface being formed by underlaps of the yarns, the elasticity of the yarns causing the underlaps to draw up and form artificial terry loops that contact the skin of the body part about which the tube is sleeved, the artificial terry loops serving to space overlaps of the yarns from the skin and to move moisture away from the skin.
 2. The skin-contacting fabric underlay of claim 1, wherein the filaments are air-jet-entangled about the core of the yarn, the filaments comprising a synthetic polymer material.
 3. The skin-contacting fabric underlay of claim 2, wherein the filaments define one or more grooves in an outer surface of each filament extending longitudinally of the filament for inducing a capillary effect to transport moisture longitudinally of the filament.
 4. The skin-contacting fabric underlay of claim 3, wherein the filaments are made of a polyester.
 5. The skin-contacting fabric underlay of claim 2, wherein the core of the yarn is made of spandex.
 6. The skin-contacting fabric underlay of claim 5, wherein the spandex comprises up to about 20 wt % of the fabric.
 7. The skin-contacting fabric underlay of claim 1, wherein the knitted structure is a tricot pattern.
 8. The skin-contacting fabric underlay of claim 7, wherein the tricot pattern is characterized by a 1-2/1-0 lapping of the yarns fed by an outer guide and a 1-0/1-2 lapping of the yarns fed by an inner guide.
 9. The skin-contacting fabric underlay of claim 1, wherein the knitted structure is a locknit.
 10. The skin-contacting fabric underlay of claim 9, wherein the locknit is characterized by a 1-2/1-0 lapping of the yarns fed by an outer guide and a 1-0/2-3 lapping of the yarns fed by an inner guide.
 11. The skin-contacting fabric underlay of claim 2, wherein the elastic core of the yarn has a size from about 10 denier to about 500 denier.
 12. The skin-contacting fabric underlay of claim 11, wherein the core is spandex and is approximately 10 to 20 denier in size.
 13. The skin-contacting fabric underlay of claim 11, wherein the yarn has a size from about 40 denier to about 840 denier.
 14. The skin-contacting fabric underlay of claim 1, wherein the tube in a relaxed state has a diameter of about 0.5 inch to about 20 inches.
 15. The skin-contacting fabric underlay of claim 1, wherein the fabric is a circular warp-knitted fabric.
 16. The skin-contacting fabric underlay of claim 1, wherein the fabric is a Raschel-knitted fabric formed on a Raschel machine having double needle bars.
 17. The skin-contacting fabric underlay of claim 1, wherein the fabric is a warp-knitted fabric formed on a flat-bed knitting machine.
 18. A method for making a skin-contacting fabric underlay for use beneath a therapeutic or prosthetic device on a human or animal body part, comprising the steps of: knitting a fabric from two sets of yarns and providing the fabric in the form of a tube, the yarns having a core of elastic material surrounded by moisture-transporting filaments of substantially non-elastic material, the yarns having elasticity, wherein the knitting is carried out so as to produce an artificial terry surface on an inner skin-contacting surface of the tube, the artificial terry surface being formed by underlaps of the yarns, the elasticity of the yarns causing the underlaps to draw up and form artificial terry loops that contact the skin of the body part about which the tube is sleeved, the artificial terry loops serving to space overlaps of the yarns from the skin and to move moisture away from the skin.
 19. The method of claim 18, wherein the fabric is formed as a tricot.
 20. The method of claim 19, wherein the yarns fed by a first yarn guide are lapped in a 1-2/1-0 pattern and the yarns fed by a second yarn guide are lapped in a 1-0/1-2 pattern.
 21. The method of claim 18, wherein the fabric is formed as a locknit.
 22. The method of claim 21, wherein the yarns fed by a first yarn guide are lapped in a 1-2/1-0 pattern and the yarns fed by a second yarn guide are lapped in a 1-0/2-3 pattern.
 23. The method of claim 22, wherein the yarn comprises an air-covered yarn in which the filaments are air-jet-entangled about the core of the yarn, the filaments comprising a synthetic polymer material.
 24. The skin-contacting fabric underlay of claim 1, wherein a distal end of the tube is fashioned with at least one finger-receiving tube constructed integrally with the remainder of the tube.
 25. The skin-contacting fabric underlay of claim 24, further comprising a thumb hole for receiving a human patient's thumb therethrough. 